Congratulations on Tofu!
I also don't have the biggest amount of experience but I do have some thoughts and questions.
I wonder if she is just becoming very 'homey' at home. In the first couple of days you may have not been a threat to her territory, but now it's hers so she's going to react differently. If that's the case then you're doing the right things, you just need to give her more time as you've only had her seven days. Just keep putting scented tissues in, and offering treats, and speaking to her, and hopefully she'll come around. I understand it must have been frustrating though to seem to suddenly go backwards, but perhaps start from scratch. Very sensible of you though to be trying to check if there's any way to improve your chances!
In terms of whether you did anything that precipitated it: when did you take her out of the cage? And how did you do so? And where did you place her to tame? My understanding is that hamsters are easier to tame outside of their territory but that it's best to use some object to remove them from the cage, to not chase them to get them out of the cage and to take them to somewhere contained like the bath tub. They should always come to you.
What sort of cage do you have her in?
I'm 100% sure someone will reply with better advice but thought I would make a starting point.
Good luck!
Best wishes,
Lydia